The invention relates to a printing ink which is to be used for printing paper and which consists of pigment, an alkyd resin binder which has been modified with fatty acids having an iodine number below 20, and, if desired, further binder and further customary constituents, such as lubricants, solvents, thickeners and thixotropic agents.
One of the starting materials in the production of newsprint is decolored waste paper in the form of an aqueous press cake. Suitable waste paper are woodfree and halftone paper, in particular paper from books, for example telephone directories. The decoloring of printed waste paper is also referred to as deinking. The decolorability of printed paper has thus gained in importance, and the interest in printing inks which lead to decolorable or deinkable prints has consequently increased.
German Offenlegungsschrift No. 3,023,118, corresponding to U.S. Pat. No. 4,383,860, discloses a printing ink which contains, as a binder, an alkyd resin which has been modified with oils, fatty acids and/or fatty alcohols having an iodine number of less than about 95. This disclosed printing ink is said to have the advantage of being readily deinkable.